The Supreme Witch, known more colloquially as The Supreme, is a worldwide status recognized among the community of witches descended from the Salem Witch Trials. While most witches possess only a handful of inherent supernatural gifts, the Supreme is said to be the living embodiment of magic itself, identified via their mastery over 7 distinct magical abilities known as "The Seven Wonders": Telekinesis, Divination, Transmutation, Pyrokinesis, Concilium, Descensum, and Vitalum Vitalis. In addition, the Supreme possesses an immunity to all pre-existing ailments and diseases, and their very presence causes the air around them to vibrate with "sheer power". Despite these talents, a Supreme may never possess the ability to perform specific feats of magic inherited by some witches via their own unique family bloodlines, such as clairvoyance, illusion manipulation, "black widow", or injury transference, to name a few.
Unfortunately, Supremacy does not last solely with one witch, as with time the next generation's Supreme will be born and the former Supreme's powers will begin to pass on to their successor. As a result, while the new Supreme flowers, the life force of the former regnant gradually fades, their immune system facing a rapid decline in the form of multiple organ failures, disease, diabetes, and cancer until their inevitable death.
Historically, witches believed there to be only one Supreme per generation (approximately 30-50 years), though this is obviously not the case. Despite Cordelia Foxx having claimed the title, Zoe Benson may prove a viable candidate for Supremacy in the future (having displayed all seven of the Seven Wonders in some form throughout the season).
In order for the Salem coven to establish a witch who has inherited Supremacy, multiple witches must undergo the Trial of the Seven Wonders - a set of tasks conducted by the Witches' Council which revolve around all seven of these aforementioned magical abilities. Whichever witch exhibits them all can then lay claim to the title of Supreme, and upon the death of their heir will inherit the full extent of their magical powers. Despite this, the risk associated with undertaking the Trial of the Seven Wonders can outright kill a witch if they do not possess the magic necessary to complete one of the Trials' specific tasks.
An exception to all established consequences of Supremacy is Scáthach, an ancient Supreme predating the Salem coven by several centuries, whose arrival to the New World during the late 1500s has followed with decades of inexplicable disappearances and violent human sacrifices in the name of "the old gods". These practices of dark and forbidding magic have granted Scáthach eternal life and unspeakable powers, at the cost of no longer appearing human.
"Guided by ancient tradition, witches survived only if united under a strong, singular authority".
The role of Supreme comes with the responsibility of protecting the Salem coven at all costs and acting as the leader of its new generation. As such, the mantle of Supremacy is not a task to be taken lightly, and there will always be a reminder in the certainty of death with the coming of a successor.
Supremes are able to act in the place of the Witches' Council and, in the event of a nonexistence council, are able to appoint new members, as was the case when Cordelia decided to replace the deceased Cecily and Quentin with Queenie and Zoe.
As the Supreme reaches their final years, one of their most important tasks is to identify their successor - a task that was neglected by former Supreme Fiona Goode. After realizing one of the witches within the coven was most likely going to surpass her, Fiona sought to find and kill them, in the hopes that she could reclaim her lost power and cure herself of her cancer. However, after the death of Fiona's presumed successor and no sole witch being able to prove themselves a true heir, multiple witches had to be tested in the Trial of the Seven Wonders in 2013, during which one witch died performing descensum.
In cases where a new Supreme must rise before the natural death of the incumbent, a ritual known as "The Sacred Taking" is employed - a stylized suicide of the Supreme blessed by the other members of the coven. It was developed when the ailing Prudence Mather, the Supreme of the 16th century, was not able to make the journey to relocate the coven from Massachusetts to New Orleans during the Salem Witch Trials; with her death, she allowed her potential successor to ascend to Supremacy. Purportedly, the Sacred Taking has only been used three times in the Salem coven's history, and only under the most extreme of circumstances.
Fiona inherited her powers earlier than most Supremes (having been around late teens to early twenties at the time) because she killed her generation's Supreme and self-ascended. Fiona lived for a short while after Cordelia's rise to the Supremacy, but had already become very weak and sickly, dying in her daughter's arms within moments of witnessing her new status.
The reigning Supreme of the Salem coven is Cordelia Foxx, who took over in 2014 from previous Supreme Fiona Goode, who was also her mother. Cordelia is the only known Supreme to have been a child of the previous Supreme, putting into question if whether or not a blood relation to the former Supreme could be a factor in inheriting their power. Fiona stated that Cordelia's place as her daughter gave her a greater influence over magic, and later claimed that when Cordelia was born, she could feel some of her power slipping away from her, which gave her the fear that someday her daughter would eventually surpass her.
Fiona's own immediate predecessor was a woman named Anna Leigh Leighton, who ran Miss Robichaux's Academy when Fiona was a younger woman, presumably around her late teens. One evening, in 1971, Fiona questioned Anna Legh about becoming the next Supreme and how she would know whether or not she was next in line. Anna Leigh informed Fiona of the official test conducted by the Witches' Council, but told her not to get her hopes up, informing her that while a witch may possess multiple powers, only a mastery of the Seven Wonders allows for a true demonstration of Supremacy. When Fiona demanded to be put to the test, Anna Leigh refused, stating she was still far too young. The two engaged in a heated debate of Anna Leigh's deterioration, both in power and physical health. After Anna Leigh asserted that she would never allow Fiona to take her place for the good of the coven, Fiona surprised her by transmutating in front of her and slashing her throat with a letter-opener, hastening her growth in power and allowing her to take Supremacy.